Methods of generation of high-energy electron beams have been investigated for the past several decades. Most common methods employ electromagnetic waves in the range of microwave or RF (Radio Frequency). However, this kind of conventional methods have a limit in acceleration gradient, which is approximately 20 MeV/m or so. As a result, high energy electron accelerators are generally big in size. Therefore, several new methods have been explored to overcome the limit in conventional accelerators. One of promising acceleration methods is to employ a plasma (See “Laser Electron Accelerator” by T. Tajima and J. M. Dawson in Phys. Rev. Lett. 43, 267 (1979)). So far several plasma-based advanced acceleration methods have been studied, but nothing is satisfactory yet.